Inhibitory Effects of Edible Green Algae Monostroma nitidum on Glycemic Responses

Abstract

We investigated the effect of edible green algae Monostroma nitidum on glycemic responses after oral administration of various saccharinity agents. Male Wister rats (6-8 weeks old) were administered 2g/kg b.w. glucose, sucrose, maltose or soluble starch with or without 0.2g/kg b.w. M. nitidum powder. M. nitidum significantly inhibited the increment of plasma glucose level (p<0.01). When we examined the three fractions of M. nitidum, that is to say, MeOH-soluble one, hot water-soluble one (crude rhamnan sulfate extract) and insoluble one on glycemic responses, rats administered crude rhamnan sulfate extract showed significantly lower plasma glucose level than the controlled group (p<0.01). Furthermore, the effects of M. nitidum and rhamnan sulfate on the postprandial increase in blood glucose level were evaluated in healthy adults. The significant deduction of the blood glucose level was observed at 30 minutes after the intake of M. nitidum powder or crude rhamnan sulfate extract compared to the controlled ones (p<0.05). These results suggests that the M.nitidum and rhamnan sulfate are useful for diabetes mellitus.